Hybrid rectifier

ABSTRACT

The hybrid rectifier includes a structurally parallel arrangement of field effect emitters and collector surfaces. Each respective emitter-collector section may be spaced apart a preselected distance to control the current density in that section. Current density in each section is also a function of the individual emitter pin sizes and geometry. This results in a device which may contain many individual sections having separate and distinct characteristics and thereby providing a multifunction hybrid rectifier.

United States Patent [191 Hagood et al. 1 1 Jan. 7, 1975 1 1 HYBRID RECTIFIER 3,745,402 7/1973 Shelton et al 313/309 1761 Jerry aged, 33333332 311332 iil .'.IIIIII"""' :iiiii: iii/383 Gap Huntsvflle, 3,772,556 11/1973 William 313/309 35803; Jeo Shelton, 700 Tatom St., Huntsville, 35 805; Ralph Primary Examiner-Archie R. Borchelt 3.644 Marymoum Assistant Examiner-Saxfield Chatmon, Jr. N.W., Huntsville, Ala. 35810 Attorney, Agent, or FirmEdward J. Kelly; Herbert [22 Filed: Dec. 6, 1973 Ber]; Jack e [21] Appl. No.: 422,495 [57] ABSTRACT The hybrid rectifier includes a structurally parallel ar- [52] U.S. Cl 313/309, 313/336, 313/340, rangement of field effect emitters and collector sur- 313/351 faces. Each respective emitter-collector section may [51] Int. Cl. H0lj 1/02 be spaced apart a preselected distance to control the [58] Field Of Search 313/309, 336, 351, 340, current density in that section. Current density in each 313/302; 321/1 section is also a function of the individual emitter pin sizes and geometry. This results in a device which may [56] References Cited contain many individual sections having separate and UNITED STATES PATENTS distinct characteristics and thereby providing a multi- 3,453,47s 7/1969 Shoulders et al. 313/351 x funcno hybrd 3,671,798 6/1972 Lees 313/309 6 Claims, 5 Drawing Figures Y A l6 l6 l2 PATENTED 7 7 sum 2 or 2 hzmmw o TIME FIG.

FIG. 3

. Governmental purposes HYBRID RECTIFIER DEoIcAToRY CLAUSE A The inventionl described herein may be manufac-' tured, used,and licensed by or for the Government for royalty th reon; I I 1 iicxoRoIuNp'oF THE NvENTIoN g There are presently threeftypes of re'ctifiersj generally without the use' of a heated filament and a collector for without payment to usv of any the emitters. Atomic radiation below thermal destruction levels does not effect the hybrid rectifier since there are no components therein that are destroyed or rendered ineffective by the radiation. Parallel emitter components of various sizes, shapes, and spacing of emitterpins allow the rectifier to have a broad range of .u'sageL The characteristics of each emitter-collector in use for electronic applications: gas filled, vacuum,

and solid state. The, gas filled rectifier is capable of drawing lar ge, currentsb ut .is limited primarily to lower v voltages because the vapor or gas breaks down at higher voltages and-arcs. T he vacuum rectifier is used 'for high voltage rectification, it has'low current output, I is fragile and requires a heated emitterzbThe heated I emitter requires a power source, resultsin excesjsive heat, and often requiresspecial cooling. Thesolid state] rectifiers are subject to operational impairment caused v by atomic radiation. 'The operational impairment of solid state rectifiersjis caused by neutrons, electrons,gamma(-y) and xfray flux. Damage maybe transient or permanent depend:

effects. Any of these effects can cause total circuit faili" ure under a radiationlenvironment due to open circuit or short circuit conditions',as a result of semiconductor disclosed in"Radiation-Effects' in Semiconductor De- "s'ection are selectable to supply the appropriate output. The. rectifier is partially or completely encasedin a vacl uum envelope-whic'h'may'be metal, glass, ceramic or:

combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a preferred embodimenhpartially in section, of the hybrid rectifier with extraneous structural Kcomponents omitted.

1 FIG. 2 is a detailed view of an emitter plate with a v collector plate .onone surface thereof.

I tifier where different electrical characteristics are employed for supplyingpower.

; FIG. 3 discloses a novel application of the hybrid rec- FIG. 4'is an'applicati on .of a single hybrid rectifier supplying both rectification and regulation for a load. FIGS 5 is aL-groupofcurves showing typical output voltagefo'b tainable fora given half-cycle input voltage.

b-E s R lPTlON OF THE PREFERRED,

f ;f.' 2.15MB DIMEN Referring the drawings wherein like numbers r r 5 representlike parts in'all figures, FIG.'1 discloses a typfailure. Additional information on this problem area is ical operational' configuration of the hybrid rectifier.

The hybrid rectifier l0 is a stack of alternately placed v collector plates IZIand e'mit ter plates 1 4. Insulating spacers-I16: are disposed .betweeni .the collector and -.f'emitter.plates- T he'i'collec tor plates-l2 arethin flat tric field-effect emission. Electric tieldeffect emission became possible with the-development: of a'iprocess which produces a material with more than a millon per' 7 square-centimeter metal rods'ernbedded'in a nietal.-.-

oxide surroundiing'. These rods (fibers or pins) may be formed to protrude from: or be-recessedinzthe'metal I oxide insulator and they maybe etched to various-sizes;

and tip configurations. This metal-oxide'matrix mare-"- rial enables electron emiss'ionat ambient temperature;

without the use of any form of emitter heater. The ma terial allows the voltage at which the device operates to be adjusted'from approximately l 00 volts to hundreds of thousands of volts'by variation'of emitter sizeand :5 I

, various sections of, thelhybridrectifier may have sepa- T-. rateor identical characteristics, dependingon the operspacing between the emitter and the c ollector,l-which the metal rods are et ched in'to the metal-"oxide matrix or by insulating spacers. Th'ey'metaloxide. matrix is more fully disclosed inU.S. Pat.- Nos. 3,745,402 and. 3,746,905 and Shelton et al., all co-in'v entors in the instant invention. U.S. Pat."No.,3,7 45,402 discloses the unique field-effect electron emitter and U.'S.'Pat.' No. 3,746,905 discloses a high. vacuum, field-effect electron tube wherein a field-effect diode is disclosed. A voltage current curve disclosed in-these. patents sets forth the typical operating voltage range of the device showing the heretofore mentioned lower limit of ap-' proximately one hundred volts.

SUMMARY oF THE INVENTION operate at ambient temperatures to emit electrons or insulation purposes as required. I v i A more detailedpv'iew of ei nitting plate 14-is showninFlG..2, the emit tingzplate's'l4consisting of a center sheets of c op pe ror.otherlgoodfconducting metal. For

'higher'.power 'operationithese"collectors may be temperature controlledfby increasing' th'ei'r thickness and passing. ccolant fluid, through spaces provided within themfThe partially cut-away view of "hybrid rectifier 10,I shows typically-the spacing between emitters l4 "and collectors'l2;.Emittin'g fibers 23 'ar'e shown proftrudirig from the insulating matrix 24 toward collectors .-12..The oxide-matrix emitters 'jare disposed inparallel 'with'the conductive support; plates. 14a therebetween' By. providing different spacing, between emitteri collectorsections's S etc. and byproviding a selectable"quantityfof emitting fibers- 23pm unit area, the

ational requirements' for each sectionilnsulation spacer 16 may be di spose d,between emitters 14 and collectors l2 andmay' be corhplet'elyiarbund the peripheryfof each emitter collector section 8 ,8 etc. for handling conductor sheet 20 with theemitting matrix 22b razed, soldered or by some other acceptable means electrically fastened to' the center conductor. The-center con emitting fibers 23 protrude from the surface 24 of the. matrix. If the fibers are etched below surface 24 ofmatrix 22, collector 12 may be joinedto the matrix surface. Typical electrical connections of copper collectors 12 are shown as lead-in conductors 26A and 26B and electrical connections for emitter plates 14 are made to electrical conductors 28A and 28B.

The hybrid rectifier is connected into an electrical circuit in the same manner as other types of rectifiers. An electric potential is applied across the rectifier from a voltage source, an electric field is generated in the region between the collector and the emitting oxidemetal matrix of each section. Since the matrix consists of a collection of ultra-fine conductors separated by an insulating, supporting structure, the electric field concentrates at the points of the ultra-fine conductors. These conductors in this material are sufficiently fine for electrons to be emitted from their points. The electrons flow to the collector plate giving a current in the circuit. The amount of current depends on the strength of the electric field, conductor diameter, and number of conductors per unit area in the matrix material. These parameters are adjusted along with total emitter and collector area for individual applications. The entire device is encased in a vacuum envelope for operation. Extreme structural rigidity may be obtained by pinning the stack together with electrically insulated bolts and shrinking a glass or ceramic envelope on the whole structure.

The rectifier differs from state of the art solid state rectifiers in that the back voltages leakage current is zero and it is not subject to atomic radiation degradation at below thermal destruction levels. These features plus its rigid construction allows better instrumentation in high flux density applications. Also since there is no back voltage leakage current, no protective resistors are required in the circuitry thereby reducing components and simplifying design.

The electrical characteristics and the simple design of the hybrid device make it possible to use it for a number of unique applications. Since the current density through each section is a function of the individual emitting pin size and geometry as well as the spacing between emitter and collector, the characteristics of each section can be specified. This results in a device which can contain many individual sections with each section having distinct characteristics. A novel application results when sections with different electrical characteristics are used as rectifiers for several power supplies as shown in FIG. 3. In this application the characteristics of each emitter and collector section are selected to supply the appropriate output, and the collectors are connected in parallelto one side of a transformer T. After conventional components suchas filter 30 is added, the hybrid device is capable of supplying a relatively consistent potential under varying load conditions when used as a voltage rectifier. In FIG. 3, the transformer T supplies the same alternating voltages to all sections represented by S S through S The output voltage from respective sections V through V, depends on the loads L through L plus the emittercollector characteristics of each section of the rectifier.

A second application is in a regulated power supply in which one or more sections (5,) are used for rectification and one or more of the other sections (S are used for regulation, since the electrical characteristics are such that they can be used for parallel voltage regulation. This circuit is shown in FIG. 4 wherein section S, of the hybrid device is connected in the conventional manner and supplies the voltage to load L. A series resistor R is placed in the circuit primarily for transformer protection, to supply a small degree of regulation, and to work in conjunction with the regulating section S The load L does not draw a uniform current flow, but varies as the load varies over an extended range of values. During operation, as the current requirements decrease less of the supply voltage is dropped across resistor R and the voltage tends to increase which results in increased current flow through S which in turn increases the current through resistor R, decreasing the voltage to the specified value across the load.

A third novel application consists of using several sections of the hybrid rectifier in parallel to shape the output current curve for special applications requiring specific rise times. In this application, the various sections have slightly different electrical characteristics, as may be obtained by emitter-collector spacing and packing density of emitting fibers. This electrical, parallel hybrid rectifier circuit may be obtained as shown in FIG. 1, by merely coupling selected sections to output leads 26-28. The resultant output typical of this application is shown in FIG. 5. As indicated in FIG. 5. the output currents from three respective sections 5 S and S when arranged in parallel, are 0,, O and 0 which combine to give the resultant output O The shape of O is determined by the design of the hybrid device and can be changed over a wide range.

Although a particular embodiment and form of the invention has been described, it will be appreciated by those skilled in the art that modifications may be made without departing from the scope and spirit of the invention. Accordingly, it is understood that the invention is limited only by the claims appended hereto.

We claim:

1. A hybrid rectifier comprising: plural parallel collector plates, plural parallel electron emitter plates disposed respectively between said plural collector plates and parallel therewith, voltage means coupled to respective of said emitter and collector plates for coupling a potential thereacross and thereby developing an electric field therebetween, said emitter plates having first and second emitting surfaces for conducting electrons simultaneously from opposing faces thereof toward respective first and second collectors in response to an electric field developed therebetween, each of said emitter plates comprise a conductive sheet sandwiched between said emitting surfaces for electrically coupling said potential thereto, and each of said emitting surfaces comprises a field-effect electron emitter having a plurality of uniformly spaced parallel emitting pins disposed normal to said conductive sheet and an oxide metal insulator disposed between adjacent pins for insulating, encompassing, and supporting said pins.

2. A hybrid rectifier as set forth in claim 1 wherein respective collector plates are spatially disposed separate and distinct distances from emitting surfaces of said emitter plates for operating in electric fields of differing strengths.

3. A hybrid rectifier as set forth in claim 1 wherein said emitting pins are terminated below the insulating oxide metal surface and respective collector plates are disposed on the surface of said oxide metal insulator.

4. A hybrid rectifier as set forth in claim 1 wherein each of said field-effect electron emitter surfaces have different emitting pin density per unit area with respect to other emitter surfaces providing selectable voltage 6 sion.

6. A hybrid rectifier as set forth in claim 1 wherein insulator spacers are disposed between adjacent emitter and collector plates for providing selected separation therebetween to control field-effect emission. 

1. A hybrid rectifier comprising: plural parallel collector plates, plural parallel electron emitter plates disposed respectively between said plural collector plates and parallel therewith, voltage means coupled to respective of said emitter and collector plates for coupling a potential thereacross and thereby developing an electric field therebetween, said emitter plates having first and second emitting surfaces for conducting electrons simultaneously from opposing faces thereof toward respective first and second collectors in response to an electric field developed therebetween, each of said emitter plates comprise a conductive sheet sandwiched between said emitting surfaces for electrically coupling said potential thereto, and each of said emitting surfaces comprises a field-effect electron emitter having a plurality of uniformly spaced parallel emitting pins disposed normal to said conductive sheet and an oxide metal insulator disposed between adjacent pins for insulating, encompassing, and supporting said pins.
 2. A hybrid rectifier as set forth in claim 1 wherein respective collector plates are spatially disposed separate and distinct distances from emitting surfaces of said emitter plates for operating in electric fields of differing strengths.
 3. A hybrid rectifier as set forth in claim 1 wherein said emitting pins are terminated below the insulating oxide metal surface and respective collector plates are disposed on the surface of said oxide metal insulator.
 4. A hybrid rectifier as set forth in claim 1 wherein each of said field-effect electron emitter surfaces have different emitting pin density per unit area with respect to other emitter surfaces providing selectable voltage ranges of field-effect emission, said emitting pins having a minimum density of one million emitting pins per square centimeter of surface area.
 5. A hybrid rectifier as set forth in claim 4 wherein insulator spacers are disposed between adjacent emitter and collector plates for providing selected spatial separation therebetween to control field-effect emission.
 6. A hybrid rectifier as set forth in claim 1 wherein insulator spacers are disposed between adjacent emitter and collector plates for providing selected separation therebetween to control field-effect emission. 